1. Field of the Invention
The present invention relates to a device to alleviate problems in the spine and more particularly to a device to replace a damaged spinal disc and promote fibrous ingrowth.
2. Description of Related Art
Back pain and spinal disorders are very common human problems. One of the major causes of these problems are damage to and degeneration of spinal discs.
The spinal disc is a shock-absorbing structure in the spaces between each vertebra in the spine. Due to age or accident, these discs deteriorate. As a result, the shock-absorbing capacity is diminished and the adjacent vertebrae contact each other. This results in wear and tear on the vertebrae and pain to the neck and back of the person.
Non-surgical treatment to reduce the pain include rest, heat, medication, physical therapy and chiropractic manipulation. Unfortunately, there are a significant number of patients for whom these treatments are unsatisfactory.
Surgical treatment usually consists of spinal fusion. However, the success rate of spinal fusion ranges from approximately 50%-90%. Even successful spinal fusion often results in stiffness and decreased mobility of the patient and stress on the spine which often produces new problems.
Because of these problems with spinal fusion, alternate treatments have been investigated. Just as there are hip and knee replacement, the concept of spinal disc replacement has been considered.
Stubstad et al in U.S. Pat. No. 3,867,728, disclosed a number of alternate embodiments. One version of the prosthesis includes a plurality of flexible, curved, bar-like elements lying side by side to occupy the interior space of a natural disc. It provides resistance to compressive forces imposed on the spine and preserves the natural flexibility of the spine.
Steffee in U.S. Pat. No. 5,071,437, disclosed an artificial disc comprised of an upper and lower flat rigid plate with a flat polyolefin rubber core interposed between the plates. Protuberances extend outwardly from the exposed surfaces of the plates for engagement with vertebrae above and below the plates. A porous coating covers the exposed surfaces of the plates.
In U.S. Pat. No. 5,320,644, Baumgartner disclosed an intervertebral disk prosthesis which imitates a natural disk. It is made of one piece from a strong, elastically deformable material such as titanium or plastic material and comprises slits at a right angle to the connecting axis which partially overlap. The overlapping regions of adjacent slits form parts of leaf springs for transmission of forces.
In U.S. Pat. No. 5,522,899, Michelon disclosed an artificial spinal fusion implant, placed within the spinal disc space, and stabilizing the spinal segment.
In U.S. Pat. No. 5,961,554, Janson et al disclosed an intervertebral spacer employing a plurality of fused, generally spherical beads of a biologically inert material (preferably titanium or titanium alloy).
Bao et al, in U.S. Pat. No. 5,976,181 disclose a prosthetic intervertebral disc nucleus to be implanted in the cavity in the spine. The implant is an elongate, partially hydrated hydrogel.
Kuras et al, in U.S. Pat. No. 6,162,252 disclose a spinal prosthesis to replace a damaged spinal disc. A body of elastomeric material is bonded to upper and lower rigid plates. The elastomeric core is a polyolefin rubber.
In U.S. Pat. No. 6,206,924 B1, Timm disclosed a three-dimensional geometric porous engineered structure for use as a bone mass replacement device.
In U.S. Pat. No. 6,214,049 B1, Gayer et al disclosed a mesh of fibrillar wires formed on an implant device. An osteoinductive coating is then formed on the wires and implant device. The combination of the coating and the fibrillar wool or prongs should allow for optimal osteointegration and physiologic load distribution of an implant device.
Although there has been some progress in recent years, most of the devices known to date have not been generally accepted and there is a need for a comparatively simple, yet effective, device.
It is an object of the present invention to provide a relatively inexpensive, simple device which is easily inserted into the spine to replace a damaged or degenerated disc.
It is a further object of the present invention to provide a replacement device which is compatible with the human body.
It is another object of the present invention to provide a replacement device which supports the growth of body fibers from the patient to incorporate the device naturally into the patient so that the body repairs itself.
In accordance with the teachings of the present invention, there is disclosed a pseudo arthrosis device disposed in a patient to support an intervertebral space between two adjacent vertebrae. The device has an enclosure having a plurality of compressible, flexible members packed longitudinally therein. The enclosure is disposed between the adjacent vertebrae. Means are provided for attaching the enclosure to at least one of the adjacent vertebrae.
In further accordance with the teachings of the present invention there is disclosed a pseudo arthrosis device disposed in a patient to support an intervertebral space between two adjacent vertebrae. The device has an enclosure formed from a flexible permeable material. A plurality of compressible flexible elongated hollow tubes are packed longitudinally within the enclosure. Each hollow tube has a plurality of spaced-apart perforations formed therein. Means are provided for attaching the enclosure to at least one of the adjacent vertebra. the enclosure is received in the intervertebral space and the hollow tubes are disposed between the adjacent vertebrae.
In another aspect, there is disclosed a method of replacing a damaged spinal disc between two adjacent vertebrae in a patient. The damaged spinal disc is removed. A pseudo arthrosis device is provided having an enclosure. A plurality of compressible, flexible members are packed longitudinally within the enclosure. At least one tab is connected to the enclosure. The pseudo arthrosis device is inserted between the adjacent vertebrae wherein the compressible, flexible members are disposed longitudinally between the adjacent vertebrae. The at least one tab is attached to at least one of the adjacent vertebrae to secure the enclosure between the adjacent vertebrae. In this manner, the pseudo arthrosis device replaces the damaged spinal disc.
These and other objects of the present invention will become apparent from a reading of the following specification taken in conjunction with the enclosed drawings.